Mold and method for forming a molded part

ABSTRACT

A mold includes a first mold portion, a second mold portion, and a projection. The second mold portion is secured against the first mold portion along a draw axis to form at least one mold cavity. The second mold portion includes an internal surface oriented at an oblique angle relative to the draw axis. The projection extends from the internal surface along a projection axis. The projection forms an elongated profile including a first end, a second ends, and a pair of side surfaces extending between the first end and the second end.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of prior-filed, co-pending U.S. patentapplication Ser. No. 15/664,547, filed Jul. 31, 2017, which claims thebenefit of U.S. Provisional Patent Application No. 62/369,494, filedAug. 1, 2016. The entire contents of these applications are incorporatedby reference herein.

BACKGROUND

The present application relates to a mold, and more specifically to amold and method for forming a feature on an inclined molded surfacewithout requiring side action.

SUMMARY

When die-casting or molding components, it can be necessary to formfeatures such as apertures on inclined surfaces. The apertures aredifficult to form during molding since the surfaces are oblique or notnormal nor parallel to the draw direction, or the axis along which themold portions are separable. Forming the features typically requires theuse of side action in the mold, or requires machining or otherpost-processing steps after molding is complete.

In one aspect, a method for forming an aperture on an inclined surfaceof a molded part includes: securing a first mold portion against asecond mold portion to form a mold cavity, the first mold portion andthe second mold portion secured along a draw axis, at least one of thefirst mold portion and the second mold portion including an internalsurface and a projection extending away from the internal surface alonga projection axis, the internal surface oriented at an oblique anglerelative to the draw axis; introducing liquid material into the moldcavity; and solidifying the material in the mold cavity around theprojection to form the molded part having at least one aperture on atleast one inclined surface.

In another aspect, a mold includes a first mold portion, a second moldportion, and a projection. The second mold portion is secured againstthe first mold portion along a draw axis to form at least one moldcavity. The second mold portion includes an internal surface oriented atan oblique angle relative to the draw axis. The projection extends fromthe internal surface along a projection axis. The projection forms anelongated profile including a first end, a second ends, and a pair ofside surfaces extending between the first end and the second end.

Other aspects of the application will become apparent by considerationof the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a mold.

FIG. 2 is an exploded view of the mold of FIG. 1.

FIG. 3 is an exploded view of the mold of FIG. 1.

FIG. 4 is a section view of the mold of FIG. 1 viewed along section 4-4.

FIG. 5 is a section view of the mold of FIG. 1 viewed along section 5-5.

FIG. 6 is a section view of FIG. 1 viewed along section 6-6.

FIG. 7A is a perspective view of a mold cavity.

FIG. 7B is a bottom view of the mold cavity of FIG. 7 a.

FIG. 8 is a side view of a projection.

FIG. 9A is a front view of the projection of FIG. 8.

FIG. 9B is an end view of the projection of FIG. 8.

FIG. 10 is a perspective view of a first mold portion.

FIG. 11 is a bottom view of the first mold portion of FIG. 10.

FIG. 12 is a side view of a molded part.

FIG. 13 is a section view of the molded part of FIG. 12 viewed alongsection 13-13.

FIG. 14 is a front section view of the molded part of FIG. 13illustrating fastener engaging the walls of the slot.

DETAILED DESCRIPTION

Before any embodiments are explained in detail, it is to be understoodthat the disclosure is not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the following drawings. Thedisclosure is capable of other embodiments and of being practiced or ofbeing carried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. Use of “including”and “comprising” and variations thereof as used herein is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items. Use of “consisting of” and variations thereof as usedherein is meant to encompass only the items listed thereafter andequivalents thereof. Unless specified or limited otherwise, the terms“mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings.

In general, the present disclosure relates to a mold which can be usedin die-casting or a similar process. Features of the mold form anaperture on an inclined or oblique surface of the molded part withoutrequiring additional machining.

FIG. 1 shows a mold 1 including a first mold portion 3 and a second moldportion 5. In the illustrated embodiment, the surfaces of the mold 1 aregenerally rectangular in shape, and the edges are curved. The first moldportion 3 and the second mold portion 5 are secured against movementrelative to one another and may be flush with respect to one another. Afirst surface 7 of the mold 1 has an injection sleeve 13 that isgenerally semi-circular in shape. In the illustrated embodiment, theinjection sleeve 13 extends only partially between an upper or secondsurface 9 and an opposing lower or third surface 11 and terminates at aninjection sleeve surface 17 that is not flush with the lower surface 11.The sleeve 13 may include a counterbore such that an opening 15positioned adjacent the second surface 9 has a larger dimension than anend of the sleeve 13 proximate the third surface 11.

FIG. 2 shows an exploded view of the mold 1 and a molded part 117. Thefirst mold portion 3 includes a first inner surface 21. In theillustrated embodiment, four tabs 23 protrude from the first innersurface 21; in other embodiments, the first mold portion 3 may includefewer or more tabs. In the illustrated embodiment, the tabs 23 arepositioned at the corners of the first inner surface 21, and each tab 23has a cross section that is generally shaped like a quarter circle; inother embodiments, the tabs may be positioned in another manner, andeach tab may have a different shape. A first round edge 25 is formedbetween the first inner surface 21 and each of the tabs 23.

FIG. 3 shows a lower exploded view of the mold 1 and the molded part117. The second mold portion 5 has a second inner surface 31. The secondinner surface 31 abuts and is sealed against the first inner surface 21(FIG. 2) when the first mold portion 3 is secured to the second moldportion 5. In the illustrated embodiment, a recess 33 is positioned ateach corner of the second inner surface 31; in other embodiments, therecesses 33 may be positioned in another manner, and/or the second moldportion 5 may include fewer or more recesses 33. The recesses 33 aregenerally complementary to the tabs 23, and each recess 33 receives onetab 23. A second round edge 35 is formed between the second innersurface 31 and the recess 33. The first mold portion 3 is secured to thesecond mold portion 5 by aligning each tab 23 so that it fits into arecess 33. When secured together, the first mold portion 3 and thesecond mold portion 5 form the injection sleeve 13.

FIG. 4 shows a section view of the mold 1. A draw axis 40 is formednormal to the second surface 9 and the third surface 11 and extendsthrough the first mold portion 3 and the second mold portion 5.

FIG. 5 is a side section view of the mold 1. The second mold portion 5includes a mold cavity surface 45. In the illustrated embodiment, themold cavity surface 45 includes a cylindrical lower portion 47 and anupper portion 49. The lower portion 47 is positioned adjacent the secondinner surface 31. The upper portion 49 includes inclined surfaces 51oriented at an oblique angle or neither perpendicular nor parallel tothe draw axis 40. In the illustrated embodiment, the upper portion 49includes five inclined surfaces 51; in other embodiments, the upperportion 49 may include fewer or more surfaces. The inclined surfaces 51are positioned around an end surface 57. In the illustrated embodiment,the end surface 57 is perpendicular to the draw axis 40. A plurality ofconduits 59 extend from the end surface 57 to the second surface 9. Inthe illustrated embodiment, the mold 1 includes four conduits; in otherembodiments, the mold 1 may include fewer or more conduits 59. Each ofthe conduits 59 are in communication with an injection aperture 61located on the second surface 9.

As shown in FIG. 6, a mold cavity 63 is formed when the first moldportion 3 and the second mold portion 5 are secured together. In theillustrated embodiment, the mold cavity surface 45 is positioned on oneside of the cavity 63, and a mold cavity interior 65 is positionedopposite the mold cavity surface 45. In other embodiments, the moldcavity surface 45 may be formed differently between the first moldportion 3 and second mold portion 5.

FIG. 7A shows an interior portion of the mold cavity 63. The mold cavityincludes a plurality of peripheral protrusions 71. In the illustratedembodiment, there are ten peripheral protrusions 71 positioned along aperimeter of the mold cavity 63, and a center protrusion 73 positionedbetween the peripheral protrusions 71 which has a generally circularcross section. The plurality of protrusions 71 and the center protrusion73 extend from the first inner surface 21 (FIG. 2). In the illustratedembodiment, the plurality of protrusions 71 and the center protrusion 73are hollow.

As shown in FIGS. 7A and 7A, an internal surface 75 is positioned on thesecond mold portion 5 opposite each inclined surface 51 (FIG. 7A). Inthe illustrated embodiment, the second mold portion 5 includes fiveinternal surfaces 75; in other embodiments, the second mold portion 5may include fewer or more internal surfaces 75. A pair of projections 77extends from each internal surface 75. In other embodiments, eachinternal surface 75 may include fewer or more projections 77.

FIG. 8 shows a side view of the projection 77. In the illustratedembodiment, the internal surface 75 extends along a plane, and theprojection 77 forms an oblique angle or an angle neither perpendicularnor parallel relative to the internal surface 75. The projection 77 alsoextends away from the internal surface 75. In the illustratedembodiment, the projection 77 has an elongated cross section. In theillustrated embodiment, the projection 77 has a trapezoidal shapedprofile. The projection 77 includes a first end 83, a second end 85, afirst side surface 86 (FIG. 9A), and a second side surface 87. The sidesurfaces 86, 87 extend between the first end 83 and the second end 85. Alower extent 88 extends between the side surfaces 86, 87 and the ends83, 85. The lower extent 88 is positioned generally perpendicular to aprojection axis 89. The projection axis 89 extends along the length ofthe projection profile. In the illustrated embodiment, the projectionaxis 89 is parallel to the draw axis 40.

FIG. 9A shows a front view of the projection 77. The projection includesa base 93 opposite the second end 85, adjacent the internal surface 75.In the illustrated embodiment, a lip 91 extends around the perimeter ofthe base 93. The lip 91 includes an elongated portion 95 and a circularportion 97. The elongated portion 95 is positioned proximate the moldcavity upper surface 57 (FIG. 4). The circular portion 97 is positionedproximate the first end 83 of the projection 77. In the illustratedembodiment, the lip 91, as well as the second end 85 and the sidesurfaces 86, 87, are rounded.

FIG. 9B shows a bottom view of the projection 77. In the illustratedembodiment, the side surfaces 86, 87 are tapered between the first end83 and the second end 85. The first end 83 has a width D1 that is largerthan a width D2 of the second end 85 and is positioned proximate thecircular portion 97.

Referring to FIG. 10, the first mold portion 3 includes a plurality offirst channels 101. In the illustrated embodiment, the first channels101 are parallel to the first surface 7 and extend to the first innersurface 21.

As shown in FIG. 11 the third surface 11 of the mold 1 includes aplurality of pin apertures 111. The pin apertures 111 lead to theplurality of first channels 101 (FIG. 10).

As illustrated in FIG. 5, the first mold portion 3 and the second moldportion 5 can have cooling apertures 113 on their outer surfaces. Eachcooling aperture 113 may be in communication with a cooling channel 115.In the illustrated embodiment, each cooling channel 115 extends from oneexterior surface to another exterior surface of the mold 1.

Referring again to FIG. 4, each of the plurality of first channels 101extends into the plurality of protrusions 71 as illustrated in FIG. 4.Each first channel 101 is aligned with one of the protrusions 71 inorder to form a continuous, hollow column.

To form a molded part, nozzles (not shown) can be inserted intoinjection apertures 61 shown in FIG. 5. Liquid material is introducedthrough the nozzles and into the mold cavity 63 (FIG. 6) through theplurality of conduits 59. Liquid material fills the mold cavity andbegins to solidify. The material solidifies around the plurality ofprotrusions 71 and the center protrusion 73. The liquid material alsosolidifies around the projections 77 and the lip 91.

To remove the molded part 117 from the cavity 63, the second moldportion 5 is separated from the first mold portion 3. Ejector pins (notshown) are inserted into the pin apertures 111 (FIG. 11) and extend intothe hollow column formed by aligning the first channel 101 and theprotrusion 71 (FIG. 4). The ejector pins push against the protrusions 71and separate the molded part 117 from the first mold portion 3 (FIG. 3).

FIG. 12 shows the molded part 117 according to one embodiment and formedby the mold 1 (FIG. 1). The molded part 117 has an outer surface 119including a first or lower portion 121 and a second or upper portion123. The upper portion 123 includes a plurality of inclined surfaces125. The projection 77 (FIG. 8) forms an elongated slot 129 in one ofthe inclined surfaces 125 of the molded part 117. The circular portion97 of the lip 91 (FIG. 9A) forms an indentation 127 adjacent one end ofthe slot 129. The indentation 127 extends into the inclined surface 125in a direction substantially normal to the associated inclined surface125. The indentation 127 is positioned proximate the molded cylindricallower portion 121. In the illustrated embodiment, the lip 91 (FIG. 9A)has a diameter greater than a diameter of an ordinary screw soindentation 127 is formed with a diameter that is greater than thediameter of an ordinary screw.

FIG. 13 shows a section view of the molded part 117. The slot 129 isformed by the projection 77 (FIG. 8) and has a similar cross section. Anaperture axis 139 is oriented normal to an inner end surface 141 andforms an oblique angle with respect to the associated inclined surface125. Due to the tapered shape of the sides 86, 87 of the projection 77(FIG. 9B), the slot 129 includes slot walls 143 that are taperedinwardly from an end 145 proximate the indentation 127 (FIG. 12) towardan opposite end 147 of the slot 129. A fastener 151 (e.g., aself-tapping screw) is inserted into the slot 129 through theindentation 127 (FIG. 12), normal to the inclined surface 125 and at anoblique angle relative to the aperture axis 139. In the illustratedembodiment, the tapered shape of the projection 77 (FIG. 9B) causes theslot 129 to have a width that decreases from the one end 145 toward theopposite end 147. As the fastener 151 is inserted, the slot walls 143extend inwardly and the threads of the fastener 151 engage the slotwalls 143 to secure the fastener 151 relative to the part 117.

FIG. 14 shows the fastener 151 secured inside the slot 129. The slotwalls 143 are tapered, and a narrow end of the slot 129 is narrower thana width of the fastener 151. The threads of the fastener 151 graduallyengage the slot walls 143 as the fastener 151 passes through the slot129. Stated another way, as the fastener 151 extends deeper into theslot 129, the threads of the fastener 151 engage more of the walls 142.

The mold 1 permits a feature (e.g., a slot 129) to be formed on aninclined surface 125 of the molded part 117 without requiring sideaction or additional mold components that can complicate the moldoperation. Side action dies result in uneven surfaces (e.g., seams)where the side action die abuts the rest of the mold, thereby creatinguneven surfaces around the resulting feature on the molded part. Anuneven surface prevents mating parts or adjacent parts from properlyabutting against the molded part. The mold 1 substantially reduces thelikelihood of uneven surfaces around the slot 129 on the inclinedsurface 125, permitting a mating part to abut the inclined surface 125in a flush manner. For example, in the embodiment of FIG. 13, the moldedpart 117 is a heat sink and the inclined surface 125 is flush with anLED board 162, thereby facilitating heat transfer from the LED board 162to the heat sink.

Although aspects have been described in detail with reference to certainpreferred embodiments, variations and modifications exist within thescope and spirit of one or more independent aspects as described.

What is claimed is:
 1. A mold comprising: a first mold portion; a secondmold portion secured against the first mold portion along a draw axis toform at least one mold cavity, the second mold portion including aninternal surface oriented at an oblique angle relative to the draw axis;and a projection extending from the internal surface along a projectionaxis, the projection forming an elongated profile including a first end,a second end, and a pair of side surfaces extending between the firstend and the second end.
 2. The mold of claim 1, wherein the sidesurfaces are tapered such that a width of the projection proximate thefirst end is larger than a width of the projection proximate the secondend.
 3. The mold of claim 2, wherein the width of the projectionproximate the second end is configured to be narrower than a width of athreaded fastener.
 4. The mold of claim 1, wherein the projection axisis oriented parallel to the draw axis.
 5. The mold of claim 1, whereinthe internal surface extends along a plane oriented at an oblique anglerelative to the draw axis.
 6. The mold of claim 1, wherein: the firstend and the second end each extend from the internal surface in adirection parallel to the projection axis; and the projection axis formsan oblique angle relative to the internal surface.
 7. The mold of claim1, further comprising a lip positioned between the internal surface andat least a portion of the projection.
 8. The mold of claim 7, wherein aportion of the lip is wider than a width of the projection proximate thefirst end.
 9. The mold of claim 8, wherein the lip includes a circularportion with a diameter configured to be wider than a width of athreaded fastener.
 10. The mold of claim 1, wherein the projection has aprofile with generally rounded edges.